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“You sort of try to set some ground rules and apologize for them,” says Kutcher, who shares spicy sequences with Natalie Portman in the racy rom-com “No Strings Attached.” “I always use Sir Lawrence Olivier – when in doubt use Sir Lawrence Olivier – and I think he said something to the affect of, like, 'I apologize if I get aroused, and I apologize if I do not get aroused.' And you have to say it with the accent.”

“In between it’s like, 'Let’s act like nothing happened,'” he adds. “And then you see how good of an actor you are.”

Kutcher confesses that performing steamy on camera can be more nerve-wracking than “performing” in real life. “You're doing the scene and you're like, 'Okay. Are they going to call cut? How far are we taking this? Are they going to call cut?' Ivan [Reitman] would come back and say, 'I think you need to orgasm sooner.' So you're male machismo is like, 'No, no, no. It would take me MUCH longer than this.' It's always slightly more complicated than it is in real life.”

Fortunately, the 6’3” actor had an easygoing camaraderie with Portman that made things easier. Despite dishing out plenty of verbal Punking to his pint-sized co-star. “It was mostly height jokes and she would get very much upset with me,” he reveals. “She looks like my child when we stand next to each other. I asked if she could reach the pedals in the car one day. That didn't go over very well.”

Published at 12:55 PM EST on Jan 21, 2011 | Updated at 2:44 PM EDT on May 30, 2012